A typical mobile device has two audio inputs. One audio input is usually an audio jack, and a second audio input is usually a built in microphone. When recording, a mobile device either records the signal received from the audio jack or from the microphone. In both cases, the mobile device typically samples the analog signal received at either the audio jack or the microphone to generate a digital signal. To determine whether to process the signal from the audio jack or from the microphone, the mobile device can include circuitry to determine whether an external device is plugged into the audio jack. If an external device is plugged in then the mobile device will process the signal from the audio jack. The mobile device may also determine that sufficient sound is being received by the microphone and use that information to process the signal from the microphone.
Like reference numbers and designations in the various drawings indicate like elements.